More accelerator code leanup

ash/accelerators/accelerator_delegate.cc

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ash/accelerators/accelerator_delegate.h"
 
 #include "ash/accelerators/accelerator_controller.h"
 #include "ash/shell.h"
 #include "ash/wm/window_state.h"
 #include "ui/base/accelerators/accelerator.h"
@@ skipping 31 matching lines @@
   }
   if (!ShouldProcessAcceleratorNow(key_event, accelerator))
     return false;
   return Shell::GetInstance()->accelerator_controller()->Process(accelerator);
 }
 
 // Uses the top level window so if the target is a web contents window the
 // containing parent window will be checked for the property.
 bool AcceleratorDelegate::CanConsumeSystemKeys(const ui::KeyEvent& event) {
   aura::Window* target = static_cast<aura::Window*>(event.target());
-  if (!target)  // Can be NULL in tests.
-    return false;
+  DCHECK(target);
   aura::Window* top_level = ::wm::GetToplevelWindow(target);
   return top_level && wm::GetWindowState(top_level)->can_consume_system_keys();
 }
 
 // Returns true if the |accelerator| should be processed now, inside Ash's env
 // event filter.
 bool AcceleratorDelegate::ShouldProcessAcceleratorNow(
     const ui::KeyEvent& event,
     const ui::Accelerator& accelerator) {
   aura::Window* target = static_cast<aura::Window*>(event.target());
-  if (!target)
-    return true;
+  DCHECK(target);
 
   aura::Window::Windows root_windows = Shell::GetAllRootWindows();
   if (std::find(root_windows.begin(), root_windows.end(), target) !=
       root_windows.end())
     return true;
 
   // A full screen window should be able to handle all key events including the
   // reserved ones.
   aura::Window* top_level = ::wm::GetToplevelWindow(target);
 
   if (top_level && wm::GetWindowState(top_level)->IsFullscreen()) {
     // TODO(yusukes): On Chrome OS, only browser and flash windows can be full
     // screen. Launching an app in "open full-screen" mode is not supported yet.
     // That makes the IsWindowFullscreen() check above almost meaningless
     // because a browser and flash window do handle Ash accelerators anyway
     // before they're passed to a page or flash content.
     return false;
   }
 
   if (Shell::GetInstance()->GetAppListTargetVisibility())
     return true;
 
   // Unless |target| is in the full screen state, handle reserved accelerators
   // such as Alt+Tab now.
   return Shell::GetInstance()->accelerator_controller()->IsReservedAccelerator(
       accelerator);
 }
 
 }  // namespace ash